I'm 25 and have worked close to 20 jobs. From teacher, to investment banker, to grad student, architectural intern, all over the place! I think that it is a common trend with our generation -- chasing interests and finding out what fits us best. Or at least it should be.
I don't think it is something to be ashamed of either. Most employers might see the quick jumps as bad things, but they are wrong. I think that each new job allows you to gain new skill sets. A person's competitive advantage comes when someone can combine skills in a way nobody else can. If someone's been at the same job for 40 years, they aren't going to be able to do that.
I opened a youth hostel in Brooklyn. We've had over 1,500 guests since opening about a year and a half ago ago. I think that the combination of all the previous jobs really helped me find what I was passionate about (traveling, real estate, customer service, teaching), and a way to combine them all into one. I'm very happy with the outcome.
We have international backpackers with us. It's my way of traveling without traveling, because I get to interact with people from all over the world all day.
Other jobs: Groundskeeper, golf cart guy, bartender, leasing consultant, research assistant, project manager for a real estate developer in Panama, English teacher, motorbike tour guide in Nicaragua, surfing instructor in Honduras, essay grader for standardized tests, library technician, club promoter, architectural intern, due diligence consultant, freelance writer